Today is the day that Apple will roll out the iOS 4.1 update for iPhone. But if you are using a jailbroken handset then do not update.

According to iPhone DEV Team, iOS 4.1 is a trap. At the moment there is no way to re-jailbreak an iPhone once iOS 4.1 is applied. In a post on the Dev-Team Blog it is clearly stated that:

There’s currently no known way to revert your baseband — if you update your baseband you’ll lose the ultrasn0w unlock, possible[sic] forever. Please stay away from this 4.1 release until a safe jailbreak procedure (which also preserves ultrasn0w) is developed and released.

A jailbreak solution may appear today, or it could take days or weeks. Until the community has had time to play with the update no one knows how difficult it will be to crack. Until then it’s best to just sit tight with iOS 4.0.1 if you prefer a jailbroken experience.